Color-plus-clear coating systems involving the application of a colored or pigmented basecoat to a substrate followed by the application of a transparent or clear topcoat to the basecoat are standard in the industry as original finishes for automobiles. The color-plus-clear systems have outstanding gloss and distinctness of image, and the clear topcoat is particularly important for these properties.
Often during application of the coatings to an automotive substrate, which is typically done by spraying, the appearance of a coating (such as its smoothness) is different when applied to a horizontally oriented substrate surface than when applied to a vertically oriented surface. This can result in noticeably different surface appearances in different areas of the same vehicle.
It would be desirable to provide a curable film-forming composition that demonstrates improved appearance properties over an entire substrate surface without loss of cured film properties such as acid etch resistance and UV durability.